What about instant green? Heck take the red bulb out entirely. Then the timeslip will tell the story.
Make it real fair, just flip a coin, just have to have a picture of a race car.
How about just drawing straws? Buy backs, sure, no problem. Plus, you wouldn't have to worry about overheating or broken parts.
But let the guys with the faster cars have the option to draw first. After all they have spent more money to make their cars faster so thay are "entitled" to choose when to draw.
But let the guys with the faster cars have the option to draw first. After all they have spent more money to make their cars faster so thay are "entitled" to choose when to draw. 
